A) Field of the Invention
The present invention relates to a semiconductor device manufacture method, and more particularly to a semiconductor device manufacture method including a process of filling a recess such as a wiring trench with a conductive member by using a damascene method.
B) Description of the Related Art
Brief description will be made on a conventional wiring forming method using a damascene method. After a recess such as a wiring trench is formed through an interlayer insulating film, a degassing process is executed at a substrate temperature of about 350 to 400° C. Thereafter, the surface of an underlying conductive member exposed on the bottom of the recess is etched by argon plasma or the like to remove a surface decomposed layer. The inner surface of the recess and the upper surface of the interlayer insulating film are covered with a barrier metal film, and a Cu seed layer is formed on the surface of the barrier metal film. Cu is electroplated to fill the inside of the recess with Cu. Unnecessary Cu is removed by chemical mechanical polishing (CMP) to leave a wiring made of Cu only in the recess.
JP-A-2004-356500 indicates that contact failure between upper and lower wirings are likely to be generated if a degassing process is executed at 350 to 400° C. According to the method disclosed in JP-A-2004-356500, occurrence of contact failure is suppressed by lowering a temperature of a degassing process to a range of 150 to 300° C.
The present inventors have found that various defects are generated during CMP if the degassing process temperature is lowered, as indicated in JP-A-2004-356500.
FIGS. 10A to 10C are sketches of electron microscopic photographs showing surfaces of Cu wirings formed by executing a degassing process at 200° C. and a damascene method. In FIG. 10A, a number of embossed defects are generated on the surfaces of Cu wirings. In FIG. 10B, hollow defects are generated in Cu wirings. In FIG. 10C, an interface between a Cu wiring and a barrier metal film is corroded and boundary corrosion defects are generated along the interface.